Preparation, spectral characterization and antibacterial studies of silver(I) complexes of 2-mercaptopyridine and thiomalate

Silver(I) complexes of 2-mercaptopyridine (Mpy), [Ag(Mpy)]NO3 and [Ag(Mpy)2]NO3, and the first mixed-ligand complex having a thione and thiolate coordinated to Ag(I), [Mpy–Ag–Tm] (Tm═thiomalate) have been prepared and characterized by IR and NMR spectroscopy. The 1H and 13C NMR spectra show the presence of both ligands in the mixed-ligand complex, [Mpy–Ag–Tm]. An upfield shift is observed in the >C═S resonance of Mpy and C═O resonances of thiomalate in 13C NMR, while the other resonances are shifted downfield. The complexes showed relatively high antibacterial activity (inhibition zone of 6–11 mm) against a gram +ve bacterium, Bacillus subtilis, as compared to that (inhibition zone of 4 mm) against a gram –ve bacterium, Escherichia coli.